To address a global environmental problem, the replacement of gasoline vehicles with electric vehicles has been increasingly important. This promotes the development of electric vehicles (EV), plug-in hybrid electric vehicles (PHEV), and hybrid electric vehicles (HEV) that use an energy storage device such as a lithium ion secondary battery as a driving source. Such energy storage device generally includes an electrode assembly having a positive electrode and a negative electrode, an electrode terminal, and a current collector for electrically connecting the electrode assembly to the electrode terminal.
In a proposed conventional energy storage device, electrode assemblies are held by connecting the electrode assemblies to a current collector, and suspending the electrode assemblies from the current collector (Refer to JP-A-2013-077546, for example). In the energy storage device, the electrode assemblies are held by connecting a plurality of legs suspending from one current collector to the respective electrode assemblies, and suspending the electrode assemblies from the current collector.